upstream/mercurial-mirror Files · mercurial/cffi/mpatch.py

dirs: resolve fuzzer OOM situation by disallowing deep directory hierarchies...

dirs: resolve fuzzer OOM situation by disallowing deep directory hierarchies It seems like 2048 directories ought to be enough for any reasonable use of Mercurial? A previous version of this patch scanned for slashes before any allocations occurred. That approach is slower than this in the happy path, but much faster than this in the case that too many slashes are encountered. We may want to revisit it in the future using memchr() so it'll be well-optimized by the libc we're using. .. bc: Mercurial will now defend against OOMs by refusing to operate on paths with 2048 or more components. This means that _extremely_ deep path hierarchies will be rejected, but we anticipate nobody is using hierarchies this deep. Differential Revision: https://phab.mercurial-scm.org/D7411

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      # mpatch.py - CFFI implementation of mpatch.c

      #

      # Copyright 2016 Maciej Fijalkowski <fijall@gmail.com>

      #

      # This software may be used and distributed according to the terms of the

      # GNU General Public License version 2 or any later version.

      from __future__ import absolute_import

      from ..pure.mpatch import *

      from ..pure.mpatch import mpatchError  # silence pyflakes

      from . import _mpatch

      ffi = _mpatch.ffi

      lib = _mpatch.lib

      @ffi.def_extern()

      def cffi_get_next_item(arg, pos):

          all, bins = ffi.from_handle(arg)

          container = ffi.new(b"struct mpatch_flist*[1]")

          to_pass = ffi.new(b"char[]", str(bins[pos]))

          all.append(to_pass)

          r = lib.mpatch_decode(to_pass, len(to_pass) - 1, container)

          if r < 0:

              return ffi.NULL

          return container[0]

      def patches(text, bins):

          lgt = len(bins)

          all = []

          if not lgt:

              return text

          arg = (all, bins)

          patch = lib.mpatch_fold(ffi.new_handle(arg), lib.cffi_get_next_item, 0, lgt)

          if not patch:

              raise mpatchError(b"cannot decode chunk")

          outlen = lib.mpatch_calcsize(len(text), patch)

          if outlen < 0:

              lib.mpatch_lfree(patch)

              raise mpatchError(b"inconsistency detected")

          buf = ffi.new(b"char[]", outlen)

          if lib.mpatch_apply(buf, text, len(text), patch) < 0:

              lib.mpatch_lfree(patch)

              raise mpatchError(b"error applying patches")

          res = ffi.buffer(buf, outlen)[:]

          lib.mpatch_lfree(patch)

          return res

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				# mpatch.py - CFFI implementation of mpatch.c
				#
				# Copyright 2016 Maciej Fijalkowski <fijall@gmail.com>
				#
				# This software may be used and distributed according to the terms of the
				# GNU General Public License version 2 or any later version.

				from __future__ import absolute_import

				from ..pure.mpatch import *
				from ..pure.mpatch import mpatchError # silence pyflakes
				from . import _mpatch

				ffi = _mpatch.ffi
				lib = _mpatch.lib


				@ffi.def_extern()
				def cffi_get_next_item(arg, pos):
				all, bins = ffi.from_handle(arg)
				container = ffi.new(b"struct mpatch_flist*[1]")
				to_pass = ffi.new(b"char[]", str(bins[pos]))
				all.append(to_pass)
				r = lib.mpatch_decode(to_pass, len(to_pass) - 1, container)
				if r < 0:
				return ffi.NULL
				return container[0]


				def patches(text, bins):
				lgt = len(bins)
				all = []
				if not lgt:
				return text
				arg = (all, bins)
				patch = lib.mpatch_fold(ffi.new_handle(arg), lib.cffi_get_next_item, 0, lgt)
				if not patch:
				raise mpatchError(b"cannot decode chunk")
				outlen = lib.mpatch_calcsize(len(text), patch)
				if outlen < 0:
				lib.mpatch_lfree(patch)
				raise mpatchError(b"inconsistency detected")
				buf = ffi.new(b"char[]", outlen)
				if lib.mpatch_apply(buf, text, len(text), patch) < 0:
				lib.mpatch_lfree(patch)
				raise mpatchError(b"error applying patches")
				res = ffi.buffer(buf, outlen)[:]
				lib.mpatch_lfree(patch)
				return res